{"product_id":"fortress-power-envy-duo-21-16kw-whole-home-solar-hybrid-inverter","title":"Fortress Power Envy Duo 21 16kW Whole Home Solar Hybrid Inverter","description":"\u003cdiv class=\"ro-page\"\u003e\n\u003cstyle\u003e\n.ro-page{max-width:1200px;margin:0 auto;color:#1D1D1D;font-family:inherit;line-height:1.6;}\n.ro-page *{box-sizing:border-box;}\n.ro-page h2.ro-h2{font-size:clamp(24px,3vw,34px);font-weight:700;margin:48px 0 16px;color:#1D1D1D;}\n.ro-page h3.ro-h3{font-size:clamp(18px,2.2vw,22px);font-weight:700;margin:0 0 12px;color:#1D1D1D;}\n.ro-page h3.ro-h3-spec{font-size:clamp(17px,2vw,20px);font-weight:700;margin:30px 0 6px;color:#1D1D1D;}\n.ro-page p{margin:0 0 14px;font-size:16px;}\n.ro-page .ro-hero{display:grid;grid-template-columns:1.1fr 0.9fr;gap:36px;align-items:center;margin:8px 0 28px;}\n.ro-page .ro-eyebrow{display:inline-block;font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:#27AAE1;background:#E9F7FC;padding:6px 12px;border-radius:999px;margin-bottom:14px;}\n.ro-page .ro-hero-video{position:relative;padding-bottom:56.25%;height:0;overflow:hidden;border-radius:14px;box-shadow:0 8px 30px rgba(0,0,0,.12);}\n.ro-page .ro-hero-video .youtube-player{position:absolute;top:0;left:0;width:100%;height:100%;}\n.ro-page .ro-hero-image{width:100%;border-radius:14px;box-shadow:0 8px 30px rgba(0,0,0,.12);display:block;}\n.ro-page .ro-trustbar{display:grid;grid-template-columns:repeat(6,1fr);gap:12px;background:#EAF6FC;border:1px solid #CBEAF7;border-radius:14px;padding:18px 12px;margin:28px 0;}\n.ro-page .ro-trust-item{display:flex;flex-direction:column;align-items:center;text-align:center;gap:8px;font-size:12.5px;font-weight:600;color:#1D1D1D;}\n.ro-page .ro-trust-item svg{width:26px;height:26px;color:#27AAE1;flex-shrink:0;}\n.ro-page .ro-feature-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin:20px 0 8px;}\n.ro-page .ro-feature-card{border:1px solid #DCEBF2;border-radius:16px;padding:22px;background:#fff;transition:box-shadow .2s ease,transform .2s ease;}\n.ro-page .ro-feature-card:hover{box-shadow:0 10px 24px rgba(39,170,225,.16);transform:translateY(-2px);}\n.ro-page .ro-feature-card svg{width:34px;height:34px;color:#27AAE1;margin-bottom:12px;}\n.ro-page .ro-feature-card h3{font-size:17px;font-weight:700;margin:0 0 8px;color:#1D1D1D;}\n.ro-page .ro-feature-card p{font-size:14.5px;color:#1D1D1D;margin:0;}\n.ro-page .ro-included{display:grid;grid-template-columns:1fr 1fr;gap:28px;margin:20px 0;}\n.ro-page .ro-included-card{border:1px solid #DCEBF2;border-radius:16px;padding:22px;background:#F5FBFE;}\n.ro-page .ro-included-card img{width:100%;max-width:320px;display:block;margin:0 auto 16px;border-radius:10px;}\n.ro-page .ro-included-card ul{margin:0;padding-left:20px;font-size:14.5px;}\n.ro-page .ro-included-card li{margin-bottom:6px;}\n.ro-page .ro-table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;margin:16px 0 8px;border-radius:8px;}\n.ro-page table.ro-specs{width:100%;border-collapse:collapse;margin:0;font-size:14.5px;}\n.ro-page table.ro-specs th{display:none;}\n.ro-page table.ro-specs tr{border-bottom:1px solid #DCEBF2;}\n.ro-page table.ro-specs tr:nth-child(odd){background:#F1F9FC;}\n.ro-page table.ro-specs td{padding:11px 14px;vertical-align:top;}\n.ro-page table.ro-specs td:first-child{font-weight:700;color:#1D1D1D;width:34%;white-space:nowrap;}\n@media (max-width:680px){.ro-page table.ro-specs td:first-child{white-space:normal;}}\n.ro-page .ro-config-scroll{margin:16px 0 8px;}\n.ro-page table.ro-config{width:100%;border-collapse:collapse;margin:0;font-size:14.5px;border:1px solid #DCEBF2;border-radius:8px;overflow:hidden;}\n.ro-page table.ro-config thead th{background:#27AAE1;color:#fff;font-weight:700;text-align:left;padding:12px 14px;font-size:14px;}\n.ro-page table.ro-config tbody tr{border-bottom:1px solid #DCEBF2;}\n.ro-page table.ro-config tbody tr:nth-child(odd){background:#F1F9FC;}\n.ro-page table.ro-config tbody td{padding:11px 14px;vertical-align:top;}\n.ro-page table.ro-config tbody td:first-child{font-weight:700;color:#1D1D1D;}\n\/* Below 640px the config table becomes stacked cards, so a theme forcing white-space:normal\n   \/ width:auto on .rte table cells cannot break it. 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8px;}\n.ro-page .ro-doc-card{display:flex;align-items:center;gap:14px;border:1px solid #DCEBF2;border-radius:14px;padding:18px;background:#F5FBFE;text-decoration:none;color:#1D1D1D;font-size:15px;font-weight:700;transition:box-shadow .2s ease,transform .2s ease,border-color .2s ease;}\n.ro-page .ro-doc-card:hover{box-shadow:0 10px 24px rgba(39,170,225,.16);transform:translateY(-2px);border-color:#27AAE1;}\n.ro-page .ro-doc-card svg{width:28px;height:28px;color:#27AAE1;flex-shrink:0;}\n.ro-page .ro-guarantee{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;background:#1D1D1D;color:#fff;border-radius:18px;padding:32px;margin:36px 0;}\n.ro-page .ro-guarantee-item{text-align:center;}\n.ro-page .ro-guarantee-item svg{width:30px;height:30px;margin-bottom:10px;color:#FFAB41;}\n.ro-page .ro-guarantee-item h4{font-size:15.5px;font-weight:700;margin:0 0 6px;}\n.ro-page .ro-guarantee-item p{font-size:13.5px;color:#BEE2F5;margin:0;}\n.ro-page .ro-note{font-size:13px;color:#6E6E6E;margin:10px 0 0;}\n.ro-page .ro-faq details{border-bottom:1px solid #DCEBF2;padding:16px 4px;}\n.ro-page .ro-faq summary{cursor:pointer;font-weight:700;font-size:16px;color:#1D1D1D;list-style:none;display:flex;justify-content:space-between;align-items:center;gap:12px;}\n.ro-page .ro-faq summary::-webkit-details-marker{display:none;}\n.ro-page .ro-faq summary::after{content:\"+\";font-size:22px;font-weight:400;color:#27AAE1;flex-shrink:0;}\n.ro-page .ro-faq details[open] summary::after{content:\"–\";}\n.ro-page .ro-faq .ro-faq-a{margin-top:10px;font-size:14.5px;color:#1D1D1D;}\n@media (max-width:820px){\n  .ro-page .ro-hero{grid-template-columns:1fr;}\n  .ro-page .ro-trustbar{grid-template-columns:repeat(3,1fr);}\n  .ro-page .ro-feature-grid{grid-template-columns:1fr 1fr;}\n  .ro-page .ro-included{grid-template-columns:1fr;}\n  .ro-page .ro-guarantee{grid-template-columns:1fr;}\n  .ro-page .ro-docs{grid-template-columns:1fr;}\n}\n@media (max-width:520px){\n  .ro-page .ro-trustbar{grid-template-columns:repeat(2,1fr);}\n  .ro-page .ro-feature-grid{grid-template-columns:1fr;}\n}\n\u003c\/style\u003e\n\u003csection class=\"ro-hero\"\u003e\n  \u003cdiv\u003e\n    \u003cspan class=\"ro-eyebrow\"\u003e16kW · 25kW Solar Input · Whole Home\u003c\/span\u003e\n    \u003ch2 style=\"font-size:clamp(26px,3.4vw,38px);font-weight:800;line-height:1.15;margin:0 0 14px;color:#1D1D1D;\"\u003eFortress Power Envy Duo 21 16kW Whole Home Solar Hybrid Inverter\u003c\/h2\u003e\n    \u003cp\u003eThe Envy Duo 21 delivers 12kW of continuous output, climbing to 16kW with solar assist, backed by up to 25kW of PV array input across three MPPT trackers — built for whole-home systems that need serious solar capacity.\u003c\/p\u003e\n    \u003cp\u003eIt's configurable to run with or without a battery, outputs both 120\/240V split-phase and 120\/208V, and carries a NEMA 4X \/ IP66 rating for demanding outdoor installs.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cimg class=\"ro-hero-image\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0623\/6055\/1667\/files\/envy-duo-21-7.jpg\" alt=\"Fortress Power Envy Duo 21 16kW Whole Home Solar Hybrid Inverter\" loading=\"lazy\"\u003e\n\u003c\/section\u003e\n\n\u003cdiv class=\"ro-trustbar\"\u003e\n  \u003cdiv class=\"ro-trust-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2l8 4v6c0 5-3.5 8.5-8 10-4.5-1.5-8-5-8-10V6l8-4z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    10-Year Warranty\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-trust-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2l2.4 7.2H22l-6 4.6 2.3 7.2L12 16.4 5.7 21l2.3-7.2-6-4.6h7.6z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    Lowest Price Guarantee\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-trust-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M20 7l-9 9-5-5\" stroke-linecap=\"round\" stroke-linejoin=\"round\"\u003e\u003c\/path\u003e\u003ccircle cx=\"12\" cy=\"12\" r=\"10\"\u003e\u003c\/circle\u003e\u003c\/svg\u003e\n    Authorized Fortress Power Dealer\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-trust-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M3 7h11v9H3zM14 10h4l3 3v3h-7z\"\u003e\u003c\/path\u003e\u003ccircle cx=\"7.5\" cy=\"18.5\" r=\"1.5\"\u003e\u003c\/circle\u003e\u003ccircle cx=\"17.5\" cy=\"18.5\" r=\"1.5\"\u003e\u003c\/circle\u003e\u003c\/svg\u003e\n    Free Shipping\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-trust-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003crect x=\"2\" y=\"5\" width=\"20\" height=\"14\" rx=\"2\"\u003e\u003c\/rect\u003e\u003cpath d=\"M2 10h20\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    0% APR Financing\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-trust-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M22 16.9v3a2 2 0 0 1-2.2 2 19.8 19.8 0 0 1-8.6-3 19.5 19.5 0 0 1-6-6 19.8 19.8 0 0 1-3-8.7A2 2 0 0 1 4.1 2h3a2 2 0 0 1 2 1.7c.1 1 .3 2 .7 3a2 2 0 0 1-.4 2.1L8 10.3a16 16 0 0 0 6 6l1.5-1.4a2 2 0 0 1 2.1-.4c1 .4 2 .6 3 .7a2 2 0 0 1 1.7 2z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    Expert Support: (303) 876-7654\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003ch2 class=\"ro-h2\"\u003eWhy the Envy Duo 21\u003c\/h2\u003e\n\u003cdiv class=\"ro-feature-grid\"\u003e\n  \u003cdiv class=\"ro-feature-card\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M13 2L4 14h6l-1 8 9-12h-6l1-8z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch3\u003e16kW Output, 25kW of Solar Input\u003c\/h3\u003e\n    \u003cp\u003e12kW continuous output climbs to 16kW with solar assist, backed by up to 25kW of PV array capacity across three MPPT trackers.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-feature-card\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003ccircle cx=\"12\" cy=\"12\" r=\"4\"\u003e\u003c\/circle\u003e\u003cpath d=\"M12 2v2M12 20v2M2 12h2M20 12h2M5 5l1.5 1.5M17.5 17.5L19 19M19 5l-1.5 1.5M6.5 17.5L5 19\" stroke-linecap=\"round\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch3\u003eDual-Phase Output\u003c\/h3\u003e\n    \u003cp\u003eDelivers both 120\/240V split-phase and 120\/208V configurations from a single inverter.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-feature-card\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2s6 7 6 11a6 6 0 0 1-12 0c0-4 6-11 6-11z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch3\u003eNEMA 4X \/ IP66 Rated\u003c\/h3\u003e\n    \u003cp\u003eA sealed enclosure rated for demanding outdoor installations.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-feature-card\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2l9 5-9 5-9-5z\"\u003e\u003c\/path\u003e\u003cpath d=\"M3 12l9 5 9-5\"\u003e\u003c\/path\u003e\u003cpath d=\"M3 17l9 5 9-5\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch3\u003eParallel Up to 10 Units, 120kW Total\u003c\/h3\u003e\n    \u003cp\u003eScale from a single inverter up to 120kW of combined AC output.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-feature-card\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003crect x=\"2\" y=\"8\" width=\"16\" height=\"9\" rx=\"2\"\u003e\u003c\/rect\u003e\u003cpath d=\"M20 11v3\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch3\u003eBattery-Optional Operation\u003c\/h3\u003e\n    \u003cp\u003eConfigurable to run with a lithium battery or without one, for grid-tied-only installations.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-feature-card\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2l8 4v6c0 5-3.5 8.5-8 10-4.5-1.5-8-5-8-10V6l8-4z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch3\u003eUL1741 and UL9540 Certified\u003c\/h3\u003e\n    \u003cp\u003eCertified to the standards that matter for grid-interactive and energy storage installations.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003chr style=\"border:none;border-top:1px solid #DCEBF2;margin:36px 0;\"\u003e\n\n\u003ch2 class=\"ro-h2\"\u003eWhat's Included\u003c\/h2\u003e\n\u003cdiv class=\"ro-included\" style=\"align-items:start;\"\u003e\n  \u003cdiv class=\"ro-included-card\"\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0623\/6055\/1667\/files\/envy-duo-21-1.jpg\" alt=\"What's included with the Fortress Power Envy Duo 21\" loading=\"lazy\"\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-included-card\"\u003e\n    \u003ch3 class=\"ro-h3\"\u003eWhat You Get\u003c\/h3\u003e\n    \u003cul\u003e\n      \u003cli\u003e1 × Fortress Power Envy Duo 21 16kW Whole Home Solar Hybrid Inverter\u003c\/li\u003e\n      \u003cli\u003eDocumentation\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp style=\"font-size:13px;color:#6E6E6E;margin:14px 0 0;\"\u003eBattery bank and solar array sold separately.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003chr style=\"border:none;border-top:1px solid #DCEBF2;margin:36px 0;\"\u003e\n\n\u003ch2 class=\"ro-h2\"\u003eFull Specifications\u003c\/h2\u003e\n\u003cdiv class=\"ro-table-scroll\"\u003e\n\u003ctable class=\"ro-specs\"\u003e\n  \u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003eFortress Power Envy Duo 21 (Envy Duo 21-US)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eContinuous AC Output\u003c\/td\u003e\n\u003ctd\u003e12,000W @ 240V \/ 12,000W @ 208V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMax Output With Solar Assist\u003c\/td\u003e\n\u003ctd\u003e16,000W @ 240V \/ 13,800W @ 208V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003ePeak Output\u003c\/td\u003e\n\u003ctd\u003e2× rated power for 0.5 seconds\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eDC Input Voltage Range\u003c\/td\u003e\n\u003ctd\u003e100–550V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMPPT Operating Range\u003c\/td\u003e\n\u003ctd\u003e120–440V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMax PV Array Power\u003c\/td\u003e\n\u003ctd\u003e25,000W\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMPPT Trackers\u003c\/td\u003e\n\u003ctd\u003e3 (2:2:1 input configuration)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMax Current Per MPPT\u003c\/td\u003e\n\u003ctd\u003e26A \/ 26A \/ 15A\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eOutput Voltage Configuration\u003c\/td\u003e\n\u003ctd\u003e120\/240V split-phase; 120\/208V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eSwitching Time\u003c\/td\u003e\n\u003ctd\u003eUnder 20ms\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eCompatible Battery Types\u003c\/td\u003e\n\u003ctd\u003eLithium battery, or no battery (grid-tied configuration)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eNominal Battery Voltage\u003c\/td\u003e\n\u003ctd\u003e48V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMax Charge\/Discharge Current\u003c\/td\u003e\n\u003ctd\u003e250A each\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eEfficiency\u003c\/td\u003e\n\u003ctd\u003ePV-to-grid 97.5%; battery-to-grid 94%; CEC 96.9%\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eParallel Capability\u003c\/td\u003e\n\u003ctd\u003eUp to 10 units, up to 120kW combined\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e22.3\"W × 35.2\"H × 11.2\"D\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e125.71 lb\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eIngress Protection\u003c\/td\u003e\n\u003ctd\u003eNEMA 4X \/ IP66\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eCertifications\u003c\/td\u003e\n\u003ctd\u003eUL1741:2021 ED3, UL9540, UL3141, OGPE\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e10 years (per Fortress Power's datasheet; full terms not listed on the product page itself)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003chr style=\"border:none;border-top:1px solid #DCEBF2;margin:36px 0;\"\u003e\n\n\u003cdiv class=\"ro-guarantee\"\u003e\n  \u003cdiv class=\"ro-guarantee-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2l8 4v6c0 5-3.5 8.5-8 10-4.5-1.5-8-5-8-10V6l8-4z\"\u003e\u003c\/path\u003e\u003cpath d=\"M9 12l2 2 4-4\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch4\u003eAuthorized Fortress Power Dealer\u003c\/h4\u003e\n    \u003cp\u003eWe sell genuine Fortress Power products backed by Fortress Power's own warranty.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-guarantee-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M12 2l2.4 7.2H22l-6 4.6 2.3 7.2L12 16.4 5.7 21l2.3-7.2-6-4.6h7.6z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch4\u003eLowest Price Guarantee\u003c\/h4\u003e\n    \u003cp\u003eFind it cheaper from another authorized dealer? Call (303) 876-7654 before you order.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"ro-guarantee-item\"\u003e\n    \u003csvg viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"\u003e\u003cpath d=\"M22 16.9v3a2 2 0 0 1-2.2 2 19.8 19.8 0 0 1-8.6-3 19.5 19.5 0 0 1-6-6 19.8 19.8 0 0 1-3-8.7A2 2 0 0 1 4.1 2h3a2 2 0 0 1 2 1.7c.1 1 .3 2 .7 3a2 2 0 0 1-.4 2.1L8 10.3a16 16 0 0 0 6 6l1.5-1.4a2 2 0 0 1 2.1-.4c1 .4 2 .6 3 .7a2 2 0 0 1 1.7 2z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n    \u003ch4\u003eReal Support, Not a Ticket Queue\u003c\/h4\u003e\n    \u003cp\u003eSizing a system or checking inverter compatibility? Call (303) 876-7654 and talk to a person.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003ch2 class=\"ro-h2\" id=\"ro-faq-heading\"\u003eFortress Power Envy Duo 21 16kW Whole Home Solar Hybrid Inverter: Frequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"ro-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat do the \"21\" and \"16kW\" in the name actually refer to?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003e\"21\" is the maximum solar PV array input this inverter accepts (up to 25kW of array capacity), and \"16kW\" is the maximum output it can deliver at 240V with solar assist — 12kW is the continuous rating without that assist.\u003c\/div\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDo I need a battery to use this inverter?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003eNo — it's configurable to run with a lithium battery or without one for a grid-tied-only setup. Call (303) 876-7654 if you want help deciding which configuration fits your goals.\u003c\/div\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this rated for outdoor installation?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003eYes, it carries a NEMA 4X \/ IP66 rating, built for demanding outdoor conditions.\u003c\/div\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I add more inverters later?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003eYes, up to 10 units can be paralleled for up to 120kW of combined AC output.\u003c\/div\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat's the warranty?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003eFortress Power's datasheet lists a 10-year warranty, though the full terms aren't published on the product page itself. Call (303) 876-7654 and we'll get written confirmation of the exact terms before you order.\u003c\/div\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I install this myself, or do I need an electrician?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003eFortress Power's equipment is designed for professional installation. We strongly recommend a licensed electrician or solar installer for any battery, inverter, or enclosure installation — call (303) 876-7654 if you need a referral in your area.\u003c\/div\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDo you offer financing or price matching?\u003c\/summary\u003e\n    \u003cdiv class=\"ro-faq-a\"\u003eYes. We offer 0% APR financing options through Affirm at checkout, and our Lowest Price Guarantee applies — if you find this product cheaper at another authorized Fortress Power dealer, call us at (303) 876-7654 before you order and we'll take care of it.\u003c\/div\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"FAQPage\",\n \"mainEntity\": [\n  {\n   \"@type\": \"Question\",\n   \"name\": \"What do the \\\"21\\\" and \\\"16kW\\\" in the name actually refer to?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"\\\"21\\\" is the maximum solar PV array input this inverter accepts (up to 25kW of array capacity), and \\\"16kW\\\" is the maximum output it can deliver at 240V with solar assist — 12kW is the continuous rating without that assist.\"\n   }\n  },\n  {\n   \"@type\": \"Question\",\n   \"name\": \"Do I need a battery to use this inverter?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"No — it's configurable to run with a lithium battery or without one for a grid-tied-only setup. Call (303) 876-7654 if you want help deciding which configuration fits your goals.\"\n   }\n  },\n  {\n   \"@type\": \"Question\",\n   \"name\": \"Is this rated for outdoor installation?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"Yes, it carries a NEMA 4X \/ IP66 rating, built for demanding outdoor conditions.\"\n   }\n  },\n  {\n   \"@type\": \"Question\",\n   \"name\": \"Can I add more inverters later?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"Yes, up to 10 units can be paralleled for up to 120kW of combined AC output.\"\n   }\n  },\n  {\n   \"@type\": \"Question\",\n   \"name\": \"What's the warranty?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"Fortress Power's datasheet lists a 10-year warranty, though the full terms aren't published on the product page itself. Call (303) 876-7654 and we'll get written confirmation of the exact terms before you order.\"\n   }\n  },\n  {\n   \"@type\": \"Question\",\n   \"name\": \"Can I install this myself, or do I need an electrician?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"Fortress Power's equipment is designed for professional installation. We strongly recommend a licensed electrician or solar installer for any battery, inverter, or enclosure installation — call (303) 876-7654 if you need a referral in your area.\"\n   }\n  },\n  {\n   \"@type\": \"Question\",\n   \"name\": \"Do you offer financing or price matching?\",\n   \"acceptedAnswer\": {\n    \"@type\": \"Answer\",\n    \"text\": \"Yes. We offer 0% APR financing options through Affirm at checkout, and our Lowest Price Guarantee applies — if you find this product cheaper at another authorized Fortress Power dealer, call us at (303) 876-7654 before you order and we'll take care of it.\"\n   }\n  }\n ]\n}\n\u003c\/script\u003e\n\u003c\/div\u003e","brand":"Fortress Power","offers":[{"title":"Default Title","offer_id":67612002058483,"sku":"Envy Duo 21-US","price":4898.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0623\/6055\/1667\/files\/envy-duo-21-7.jpg?v=1790785820","url":"https:\/\/renewableoutdoors.com\/products\/fortress-power-envy-duo-21-16kw-whole-home-solar-hybrid-inverter","provider":"Renewable Outdoors","version":"1.0","type":"link"}